If you use a Catalyst 2950 switch command, it might not be supported on the Catalyst 2960 switch. The Catalyst 2960 switch software handles the incompatible commands in these ways:

•They are accepted and translated. A message appears.

•They are rejected. A message appears.

In most cases, configuration files are loaded without rejections. Table C-1 lists the Catalyst 2950 exceptions. The features are listed in alphabetic order, with Catalyst 2950 commands and explanations, and the resulting action on the Catalyst 2960 switch.

If you have a custom QoS configuration on the Catalyst 2950 switch, we recommend that you use auto-QoS for transition to the Catalyst 2960 switch.

Note If auto-QoS does not provide the configuration required for your network, we recommend that you remove the QoS configuration on the Catalyst 2950 switch and create a new configuration on the Catalyst 2960 switch.

The Catalyst 2960 switch accepts the auto qos command and generates QoS commands that are appropriate for the Catalyst 2960 switch. The policer granularity is adjusted to 1 Mbps.

For more information about the generated commands, see the auto qos voip command in the command reference for this release.

Auto-QoS is not enabled on the Catalyst 2950 switch, but other QoS commands are configured.

Feature Behavior Incompatibilities

Some features behave differently on the Catalyst 2950 and Catalyst 2960 switches, and some features are not supported on the Catalyst 2960 switch:

•Access control lists (ACLs)

Even though the command syntax is the same on the Catalyst 2960 switch and on the Catalyst 2950 switch, the semantics of the IP and the MAC ACL between the two platforms differ. For example, you can apply MAC ACLs for IP packets on the Catalyst 2950 switch, but on the Catalyst 2960 switch:

–You cannot apply MAC ACLs to IP packets.

–You cannot apply any ACLs for IPv6 frames.

–With MAC ACLs, an Ethertype of Appletalk is not supported.

•QoS

The Catalyst 2960 switch uses different port hardware than the Catalyst 2950 switch, and more QoS features are offered on the Catalyst 2960 switch. For example, the Catalyst 2950 switch supports WRR scheduling, whereas the Catalyst 2960 switch supports SRR scheduling. Also, you must enable QoS globally on the Catalyst 2960 switch, whereas QoS is enabled by default on the Catalyst 2950 switch. For more information, see "Configuring QoS."

•RSPAN

The Catalyst 2950 switch uses an extra port, called the reflector port, for its RSPAN implementation. This is not necessary in the Catalyst 2960 switch RSPAN implementation. The Catalyst 2960 switch also supports VLANs as SPAN sources and can forward received packets on SPAN destination ports.

•Multicast

The multicast forwarding decisions on the Catalyst 2960 switch are based on IP addresses. Some Catalyst 2950 switch workarounds to address platform limitations (such as the ip igmp snooping source-only-learning global configuration command) are not required on the Catalyst 2960 switch.